The present invention relates to an endoscope guide tube unit and a tissue resecting method for use, for example, as a rectoscope for performing a treatment through the anus, and as a guide tube unit for guiding a laparoscope into a narrow site in a treatment tract upon surgical operation under the laparascope.
Conventionally, the surgical operation to be performed through the anus of a human subject is broadly classified into (1) a through-the-anus surgical operation through a direct observation under an anoscope and (2) a mucosa resecting procedure endoscopically performed under an optical system (hereinafter referred to as a scope) fitted in a cylindrical member initially inserted into the anus of the human subject and having a size somewhat greater than the anoscope.
The mucosa resecting procedure (2) using such an endoscope can be applied to a considerably deeply-seated lesion as compared with a directly observed surgery (1) under the anoscope. The sheath of the guide used for the procedure (2) is 40 mm in outer diameter and about 10 to 20 cm in length. The forward end portion of the sheath is diagonally cut away and the proximal-end portion of the sheath is hermetically sealed with an air-tight connector. In use, the endoscope is hermetically fixed in place at the connector and a treating tool, such as forceps, is hermetically inserted into an inside and the procedure is carried out while making an observation under the endoscope. At that time, a CO.sub.2 gas is sent via the sheath into the rectus where a treatment space is positively created due to the expansion of the rectus with the CO.sub.2 gas.
Further, upon the resection of the mucosa, a physiological salt solution is injected below the mucosa to cause that area to be raised. By doing so, the mucosa is cut off with a high-frequency current. After the cutting off of the mucosa, the parts of the cut area are stitched together, thus ensuring an earlier recovery and preventing a narrowing from occurring due to ulceration at that cut region. It is required that a suture line be formed in a direction perpendicular to the longitudinal axis of the intestinal tract.
According to these methods, it is possible to cut off the lesion in the body of the patient without the need to open his or her body wall and it is useful from an invasive standpoint.
In the case where the procedure (2) is not used, the abdomen is dissected as a replacement procedure and a very great invasive procedure is required, such as a "forward removal" by cutting the rectus and a trans-sacral removal by cutting the side portion of a tailbone and sub-sacral bone down to the neighborhood of the anus. It is said that the procedure of the removal of the mucosa, under the endoscope, through the anus is very useful to the patient.
As the surgical instrument, there is a connector-equipped sheath, for example, in U.S. Pat. No. 4,538,594 and DE 3319049 C2. This can be used for procedure by the insertion and holding in place of an optical device (scope) and forceps.
Further, a double-sheath unit is known in GM 91 15 741.2, having a similar structure to that shown above and, in particular, an inner and an outer tube projecting from the outer tube and exchangeable with a new one.
Still further, a rectoscope having a similar structure is also known in GM 83 16 987.3 in which an opening is provided in the side wall of a distal-end portion of a sheath to be inserted into the rectus through an anus and a connector with a light source cable mounted thereon is rotatably mounted on a proximal-end side of the sheath and, upon the insertion and withdrawal of the sheath, the opening of the sheath is closed by a closing means.
In the case where any treatment is performed on a narrow cavity by a surgical operation under a laparoscope, it has been the usual practice to, while creating a treating space with the use of a plurality of forceps and excluding tool, treat that region of interest by another forceps, etc.
In U.S. Pat. No. 4,538,594, DE 3319049 C2 or GM 83 16 987.3, a treatment is performed by injecting a CO.sub.2 gas into the rectus through a sheath and expanding the rectus with the CO.sub.2 gas. A port with a hermetic seal maintaining means is provided on a connector section so as to insert forceps, etc., into a region when a gas is sent there. Therefore, the forceps, etc., for treatment is gripped at the hermetic seal section and, upon the operation of the forceps, etc., that operation or operations are considerably restricted at that hermetic seal section-equipped port side acting as a fulcrum. In order to cover such a restricted movement, the forward end portion of the forceps, etc., is so designed as to be somewhat bendable. If, that end portion is so bent, then the operability of the forceps, etc., is affected, so that a treatment has to be performed under a very difficult condition.
Further, as shown in FIG. 21A, a treatment space 200 at a rectus expanded with a gas provides a three-dimensional space deeper from an obliquely opened end position of a sheath 201. For this reason, the treating operation in the treatment space 200 has to be done under a complicated three-dimensional motion and a higher degree of skill, coupled with the operational difficulty, has been needed under these situations.
After the insertion of the sheath into the rectus, it is so positionally set as if to look down onto a lesion 202 from an obliquely opened end of its distal end side through the treatment space 20. Further the treatment space 200 is three-dimensional and, in addition, the lesion 202 also takes various positions though depending upon the running of the rectal tract, so that the treatment has often been performed under a difficult condition. In the case where any lesion 202 is situated at an upper, a middle or a lower rectal valve and, in particular, at the backside of a valve so-called the rectal folds 203, the treatment space becomes difficult to observe under a scope 204 due to it defining the deeper three-dimensional space as set out above. Moreover, the lesion 202 also becomes difficult to obtain in a visual field. Thus it has been fairly difficult in actual practice to appropriately perform a treatment including the removal of the mucosa.
Further, when, after the removal of the lesion 202, the parts of the cutting region are stitched together, that suture line has to be oriented toward the direction perpendicular to the longitudinal axis of the intestine. If this direction is wrongly taken, then there is a possibility that a narrowing is created in the intestinal tract. Thus a careful operation is needed upon suture. Further, the sheath 201 is maintained in a hermetic state and the stitching method is a continuous suture done by a general surgery under a laparoscope, thus involving a difficult operation of, for example, correctly passing a thread needle from the forceps on one side to the forceps on the other in the sheath 201.
Since, in the above technique, generally, the longer the sheath, the smaller the degree of freedom with which the forceps are oriented, that is, in particular, the smaller the angle at which the suture line is oriented relative to the longitudinal direction of the intestinal tract, it follows that, under these situations, the deeper the lesion is situated, more difficult an operation is needed.
Further, various types of special-purpose tools/instruments are required, such as a gas supply device, a smoke removing device upon conduction with a high frequency, a sealing member at a connector, etc.
In order to avoid these situations, another method has also been attempted whereby no air is conducted (no connector is provided). FIG. 21B shows the method according to which an oblique distal-end portion of a sheath 201 is pushed against a lesion 202 without passing any gas thereto and, by doing so, a treatment is performed there at that operation field. Generally, a mucosal tissue 206 of the rectal tract is more distensible and, if the distal-end portion 205 of the sheath 201 is pushed against the mucosal tissue 206, the mucosal tissue portion enters clear of a sheath's distal-end 205 into this sheath 201, so that the lesion 202 is much less extended/distended. It is actually difficult to, in this state, cut off that layer region of the mucosal tissue 206. And there is a risk that the region will be pierced instead of being cut off or partly left as it is. This forces the operator to take a very careful operation under a difficult condition.
The design of not supplying any gas eliminates the need to provide a corresponding special-purpose device, indeed, and adds the degree of freedom because the associated forceps as a whole can be moved without the need to provide any fulcrum there. This advantage is offset by the disadvantage that, since, conversely, the mucosal tissue portion of the intestinal track glides into the opening of the distal end portion of the sheath, the lesion cannot be adequately developed and be difficult to obtain along a planned cutting-off line.
Since, upon surgery under the laparascope, a treatment is performed at a narrower tract, this procedure is very cumbersome and there is a poor development of the region in a surgery field, so that, if there occurs the bleeding, etc., it is difficult to control.
As set out above, the conventional procedure has a merit in one aspect but a demerit in another aspect and is difficult, thus requiring a skilled technique.